Electromagnetic fields are almost impossible to get away from in our modern environment—they come from phones, televisions, radios, power sockets and even from thunderstorms. And while we go about our day, blithely unaware of the currents around us, a student at the University of the Arts in Bremen, Germany, decided that he would attempt to harvest their energy. As a result, Dennis Siegel created a small device that can be placed near the source of a field to charge batteries, creating energy from the wasted energy all around us.

The electromagnetic harvester, as Siegel calls is, taps into electricity currents to slowly charge any run-of-the-mill battery. By just placing the harvester near a current, the device will go to work, giving you a freshly charged battery—which, for an AA battery, could take about a day to complete. An LED light indicates when you have located a good source and a built-in magnet means that you can attach the device to metal and leave it while it is charging.

Siegel created two different harvesters, one for low frequency currents and one for high frequency currents, so a broad range of fields can be utilized. The technology uses coils and high frequency diodes to capture all of that latent energy, and while it might not be ready for charging larger items just yet, it certainly opens up a world of new opportunity for harvesting the power that surrounds us every day.